#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pld = pair<ld, ld>;
#define fi first
#define se second
#define left BAO
#define right ANH
#define pb push_back
#define pf push_front
#define mp make_pair
#define ins insert
#define btpc __builtin_popcount
#define btclz __builtin_clz
#define sz(x) (int)(x.size());
#define all(x) x.begin(), x.end()
#define debug(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int d4x[4] = {1, 0, -1, 0}; int d4y[4] = {0, 1, 0, -1};
int d8x[8] = {0, 1, 1, 1, 0, -1, -1, -1};
int d8y[8] = {1, 1, 0, -1, -1, -1, 0, 1};
template<class X, class Y>
bool minimize(X &x, const Y &y) {
if (x > y)
{
x = y;
return true;
}
return false;
}
template<class X, class Y>
bool maximize(X &x, const Y &y) {
if (x < y)
{
x = y;
return true;
}
return false;
}
const int MOD = 1e9 + 7; //998244353
template<class X, class Y>
void add(X &x, const Y &y) {
x = (x + y);
if(x >= MOD) x -= MOD;
}
template<class X, class Y>
void sub(X &x, const Y &y) {
x = (x - y);
if(x < 0) x += MOD;
}
/* Author : Le Ngoc Bao Anh, 12A5, LQD High School for Gifted Student*/
const ll INF = 1e9;
const int N = 73;
int d[N][N], dp[N][N][N];
void BaoJiaoPisu() {
int n, m; cin >> n >> m;
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= n; j++) d[i][j] = INF;
d[i][i] = 0;
}
for(int i = 1; i <= m; i++) {
int u, v, w; cin >> u >> v >> w;
minimize(d[u][v], w);
}
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= n; j++) {
for(int x = 0; x <= n; x++) {
dp[i][j][x] = INF;
}
}
dp[i][i][0] = 0;
for(int x = 0; x < n; x++) {
for(int j = 1; j <= n; j++) {
for(int t = 1; t <= n; t++) minimize(dp[i][t][x + 1], dp[i][j][x] + d[j][t]);
}
}
}
int k, q; cin >> k >> q;
minimize(k, n);
while(q--) {
int u, v; cin >> u >> v;
int ans = INF;
for(int i = k; i >= 0; i--) {
minimize(ans, dp[u][v][i]);
}
if(ans == INF) ans = -1;
cout << ans << '\n';
}
}
int main()
{
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int tc = 1, ddd = 0;
// cin >> tc;
while(tc--) {
//ddd++;
//cout << "Case #" << ddd << ": ";
BaoJiaoPisu();
}
}
